1. Field of the Invention
The present invention relates to an image retrieval system and method, and more particularly, to an image retrieval system and method that searches a collection of secured image data to provide a user with an image corresponding to a query specified by the user.
2. Discussion of the Background
Image retrieval systems enable computer users to search for and view desired images on a computer display by specifying a query term relevant to the image data. Various methods have been proposed to manage image data in such retrieval systems, some of which feature enhanced security to prevent unauthorized access or viewing of confidential information contained in the image data.
For example, one conventional method controls access to image data that has annotations (i.e., explanatory notes, highlights, lines, polygons, etc.) superimposed on the image contents. This data retrieval system uses separate tables to manage different access levels for image data and for annotation data. Upon receiving a query specified by a user, the system references the image data management table to retrieve an image that is relevant to the specified query and matches the user's access level. The system then references the annotation data management table to determine whether or not the annotation for the retrieved image also matches the user's access level, and outputs only that data having both image and annotation contents available for that particular user.
A drawback of the conventional method is that a user cannot access image data which is generally relevant to the specified query, but contains some confidential information not matching the user's access level. Such unavailability of relevant data is inconvenient to users wishing to access as much information as possible, making the system functionally less advantageous than it could be.